Infective Endocarditis

by Michael_Koger

Infective endocarditis is a well-known illness in which bacteria enter the human bloodstream, Medical doctors have known about it since the 19th century [1].

Clinicians also refer to this infirmity as subacute bacterial endocarditis. It may occur as an acute or chronic condition. Microorganisms may lodge in the lining of the human heart or blood vessel. Damage to the endocardium leads to it. The result may be microbes which occur in the cardiac valves. Nevertheless, it is not common [1, 2, 3].

When it is acute, it may become life-threatening in several days. Chronic cases, on the other hand, may happen over a period of several weeks or months. There is also a connection with poor dental hygiene. Specifically, there may be injury somewhere in the oral cavity, and this can lead to it [1, 2, 3].

Risk Factors

     As with any malady, there are well-known risk factors for it.  For example, birth defects of the human heart in young people may occur.  These cases may demonstrate leakage of blood to another part of the heart.  Moreover, adults can acquire it as a result of previous surgical procedures or transplant of that organ [1, 2, 3]. 

     Of course, congenital heart defects or a prior occurrence will place the client at risk.  Furthermore, illegal drug use intravenously is a well-known factor which can damage the tricuspid valve of the heart.  It can therefore occur in young or old patients [1, 2, 3].

     In fact, infective endocarditis will vary in its distribution across the globe.  One interesting example is the presence of rheumatic fever in poor countries.  This situation creates a predisposition.  Another example is prolapse of the mitral valve in developing countries and the occurrence of this infirmity.  Nevertheless, permanent pacemakers and cardioverter defibrillators will lower risk for this [1].   

     Extensive interactions with the health care system may also create a predisposition for it [1].  One issue which physicians must consider is the distribution of microorganisms which lead to it.  Specifically, Streptococcus and Staphylococcus arewell-known sources of it.  However, their occurrences vary over the years as well as geographic location.  Sometimes the patient may receive antibiotic therapy before the physician begins the diagnostic workup, and the result is obviously misleading [1].

Clinical Course

     This illness manifests many signs and symptoms which also take place in other infectious diseases.  For example, these individuals may have fever, chills, night sweats, and fast heart rate.  There may be fatigue, joint or muscular aches, cough and swelling of the abdomen, feet, or lower extremities.  In any event, treatment requires antimicrobial therapy in high doses over several weeks [1, 2, 3]. 

     It is also possible to prevent some of these scenarios with antibiotic therapy prior to certain   dental, surgical, or other medical procedures [1, 2, 3].  There has, however, been controversy about these uses of antimicrobial agents.

     The serious nature of infective endocarditis does not necessarily keep the human immune system from protection.  This includes, of course, humoral and cellular immunity.  Macrophages will appear in the peripheral blood.  Splenic enlargement is another way the human body reacts to the situation.  The human body will generate opsonic antibodies, complement fixation antibodies, and cryoglobulins.  Agglutination antibodies are well-known items which will come to the defense. [1].

     Cardiac abnormalities will enter the picture as vegetations.  These include valve leaflet problems of the mitral, tricuspid, aortic, and pulmonary valves.  Naturally, the patient is at risk for acute myocardial infarction [1].

     Another item of interest is mycotic aneurysm as they may not become evident to the clinician for several years.  Moreover, autopsy findings in these clients have demonstrated the presence of splenic infarcts.  There are also cases with small emboli in blood vessels, and this leads to septic pulmonary emboli [1].

     Skin lesions in this disease may include Janeway lesions, Osler’s nodes, petechiae, and cutaneous infarcts.  Eye abnormalities may occur with hemorrhage of the retina and a central region of pale appearance [1].

Diagnostic Approaches

     There are many ways to evaluate these clients as technology has grown over the decades.  The current recommendation is to begin with an echocardiogram.  A transthoracic echocardiography (TTE) may be quite a sensitive examination for the detection of vegetations.  Despite this knowledge, the location of inflammation and other clinical findings will still determine the efficacy of that procedure [1, 2]. 

     It is like anything else in medicine—the whole picture enables the physician to make a decision that is best for clinical management [1, 2].

Prevention of Endocarditis

     Mention of prophylactic measures against this infirmity is in order.  In fact, there has been controversy over the years about this issue.  Well-known medical organizations in Europe and the United States have suggested that bacteremia can occur when one chews food, flosses, or brushes the teeth.  A common question has to do with prophylactic antibiotic therapy and cardiac patients.  Is this an issue with dental procedures as well?  The literature varies across the globe on these matters [1].

     Obviously, such scenarios require an interdisciplinary team with the cardiac surgeon, general internal medicine specialist, cardiologist, and infectious disease specialist.  Either way, the physician who does administer antimicrobial therapy must interpret them correctly.  Specifically, in order to determine whether the infection has ended, one must draw blood cultures every 24 to 72 hours.  Of course, this must accompany proper serologic studies and sensitivities with those blood cultures [1].


     The diagnosis and management of infective endocarditis has changed over the decades, and the occurrence has changed as well.  Hence, its diagnosis and management are not entirely the same.  Nevertheless, the decisions for diagnosis and management will vary with geographic regions in the world.


  1. Holland, T., Baddour, L., Bayer, A. et al.  (2016).  Infective endocarditis.  Nature Reviews Disease Primers, 2, 16059.
  2. Mgbojikwe, N., Jones, S., Leucker, T., and Brotman, D.  (2019).  Infective endocarditis:  Beyond the usual tests.  Cleveland Clinic Journal of Medicine, 86, 559-567.
  3. American Heart Association.  (2019).  Heart valves and infective endocarditis.
  4. The photo shows a stethoscope and is reprinted with permission from the U.S. Centers for Disease Control.
  5. Copyright 2019 Michael Koger, Sr.  All rights reserved.


     The information contained in this article is for educational purposes only, and one should not use it for diagnosis or treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact their physician for advice.


Updated: 09/26/2019, Michael_Koger
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